320 Surgical Treatment
Force platform gait analysis
Force platform gait analysis provides an objec-
tive, sensitive method to measure gait. It has
been used extensively to compare forces before
and after surgical treatment of CR in clinical
patients (Budsberget al.1988; Dupuiset al.1994;
DeCampet al.1996; Jevenset al.1996; Marsolais
et al.2003; Conzemiuset al.2005), and is recog-
nized by many as the ‘gold standard’ outcome
measure for orthopaedic conditions such as CR.
However, computational gait analysis is useful
only if cases are carefully selected, the gait anal-
ysis is precisely performed, and the collected
data are correctly analyzed (Evanset al.2003;
Evanset al.2005).
Pressure platform gait analysis can also be
used and has specific advantages and disad-
vantages that are relevant to clinical research.
Tek-scan’s Industrial Sensing pressure mea-
surement system has been compared to tradi-
tional force platform gait analysis, and the data
are comparable (Besanconet al. 2003). However,
the data are not interchangeable because pres-
sure mats consistently underestimate vertical
forces; thus, studies should choose one method
or the other. This system has been used suc-
cessfully to evaluate limb function in dogs after
surgical treatment of CR (Horstmanet al. 2004).
A final alternative is to use the pressure-sensing
mat GAIT4Dog®. These mats do not report pad
pressures or ground reaction forces, which lim-
its validation techniques, but rather report rela-
tionships between limbs, such as asymmetry.
Their long length allows for the rapid collection
of data and their integration into treadmills is
unique.
Reporting data in a clinically
meaningful manner
Many investigators including the present
authors have limited the usefulness of their
data by only reporting group means and p-
values. If it is reported that the peak vertical
force is 40.0 for group A and 38.0 for group
B, and theP-value is 0.04, then clearly group
AandBaredifferent.IfGroupAandBhave
undergone different surgical procedures, then
this result tells us very little clinically. What
owners and veterinarians need to know is
how a difference impacts the outcome for an
individual dog, what is the size of the differ-
ence, and is it clinically significant? Although
these topics extend beyond the scope of this
chapter, investigators should consider report-
ing probability, such as probability of normal
function (Conzemiuset al.2005), effect sizes of
group differences, and then consider clinical
significance from these results.Additional considerations regarding
residual lamenessThree additional potential contributors to resid-
ual lameness in a dog after CR stifle stabiliza-
tion surgery are the development of compli-
cations, the progression of OA, and instability.
While many complications are avoidable, their
exclusion is impossible. Complication rates
have been reported for many studies, and their
relative frequency between various stabiliza-
tion techniques estimated by some authors. A
clear definition of the timing and severity of
a complication has been described and should
be used for consistency (Cooket al. 2010). As
discussed above, complications need to be con-
sidered with successes. For example, Vosset al.
(2008) used force platform gait analysis to deter-
mine outcome in dogs after tibial tuberosity
advancement, and reported that while most
dogs returned to a function that was 90% of the
normal dogs studied, 25% of the cases had a
complication and these dogs had ground reac-
tion forces (GRFs) that were significantly lower
than when no complication occurred (Vosset al.
2008).
OA development and progression is
inevitable regardless of the surgical tech-
nique used. While the severity of stifle OA
is not correlated to the severity of lameness
(Gordonet al. 2003), it seems likely that dogs
with OA have a greater probability of lameness
as compared to their counterparts. Much of this
assertion could be related to the limitations of
plain radiographs. Magnetic resonance imag-
ing (MRI), using dGEMRIC or T2 mapping, can
generate objective information regarding the
health of the cartilage, is related to OA progres-
sion and patient prognosis (Cunninghamet al.
2006; Welschet al. 2009), and has been described
in the dog (Wuchereret al. 2012). One aspect
of stifle surgery that some surgeons consider
routine is medial meniscus release, which aims